The ClusterPartition is just the management ojbect for configuring the HAPartition implementation details. Supporting configuration of the HAPartition Impl via a pojo exposing the dependencies and configuration properties is the way to go. Just make sure to loose the explicit dependency on xml.
ClusterPartition/HAPartitionImpl will no longer accept an XML element with the JGroups protocol stack. Rather it uses injected refs to a JChannelFactory and the name of the stack config to use. The JChannelFactory is then responsible for providing the channel.
So, the configuration requirements for HAPartitionImpl are pretty simple -- injection of needed services, plus a few primitive properties. Were you talking about a separate configuration pojo largely because of complexity related to the protocol stack config (which no longer exist) or is that a general approach to service configuration that you want in AS 5?
The above doesn't remove the issue of XML-based configuration of JGroups; it just moves it to a different place (the JChannelFactory.) Configuring a JChannel via a POJO is something I'll have to take up with Bela; JBoss Cache is going to need the same kind of thing.